I wager, in fact, that the poor woman has become Didyme for all intents and purposes

If she has, that might imply that Elspeth's power doesn't just send memories/experiences, but also personality traits. Or that identifying strongly with a set of absorbed memories is enough to give you those personality traits (I don't really like that theory).

The bond might or might not be affected by personality, but I'm not sure I could consider her to be "Didyme resurrected in a new body" (or even just "close enough") unless the personality was basically Didyme's (or close enough).

Ironically, the reversal test often fails, though: that is, it's not uncommon for people to intuit that a copy of X that lacks trait Y isn't really X, while at the same time intuiting that if X were to lose trait Y, it would still be X.

Identity is complicated.

For my own part, I think the terms "memory" and "personality trait" stop being clearly distinguishable from one another, when you drill down into implementation. Our brains create persistent data structures in response to events, and those data structures underlie both personality and memory. That distinction is functional -- we distinguish a personality trait from a memory based on how we behave, not based on any kind of awareness of the underlying data structures. And it's not at all obvious (nor even likely) that all the things we call "memory" share a common data structure, or that they don't share underlying data structures with what we call "personality."

Then again, I feel the same way about "identity."

To understand an elephant is to realize that recognizing the difference between trunk and tusk is not the end of the story.

So I would expect a psychic power that interacted with those data structures not to respect the boundaries between "memory" and "personality" in any kind of intuitive way.

That said, many witch-powers in this fictional world do respect those intuitive boundaries, so it's not clear what any of the above actually has to do with events in the story.

If she has, that might imply that Elspeth's power doesn't just send memories/experiences, but also personality traits. Or that identifying strongly with a set of absorbed memories is enough to give you those personality traits (I don't really like that theory).

Or that Paola and Benito were already similar in personality to Didyme and John, although that's a bit of a coincidence.